Detecting Aspergillus-specific IgG is critical to diagnosing chronic pulmonary aspergillosis (CPA). Existing assays are often cost- and resource-intensive and not compatible with resource-constrained laboratory settings. LDBio Diagnostics has recently commercialized a lateral flow assay based on immunochromatographic technology (ICT) that detects Aspergillus antibodies (IgG and IgM) in less than 30 min, requiring minimal laboratory equipment. A total of 154 CPA patient sera collected at the National Aspergillosis Centre (Manchester, United Kingdom) and control patient sera from the Peninsula Research Bank (Exeter, United Kingdom) were evaluated. Samples were applied to the LDBio Aspergillus ICT lateral flow assay, and results were read both visually and digitally. Results were compared with Aspergillus IgG titers in CPA patients, measured by ImmunoCAP-specific IgG assays. For proven CPA patients versus controls, sensitivity and specificity for the LDBio Aspergillus ICT were 91.6% and 98.0%, respectively. In contrast, the routinely used ImmunoCAP assay exhibited 80.5% sensitivity for the same cohort (cutoff value, 40 mg of antigen-specific antibodies [mgA]/liter). The assay is easy to perform but challenging to read when only a very faint band is present (5/154 samples tested). The ImmunoCAP Aspergillus IgG titer was also compared with the Aspergillus ICT test line intensity or rate of development, with weak to moderate correlations. The Aspergillus ICT lateral flow assay exhibits excellent sensitivity for serological diagnosis of CPA. Quantifying IgG from test line intensity measurements is not reliable. Given the short run time, simplicity, and limited resources needed, the LDBio Aspergillus ICT is a suitable diagnostic tool for CPA in resource-constrained settings.

Background Early recognition and diagnosis of allergic bronchopulmonary aspergillosis (ABPA) is critical to improve patient symptoms, and antifungal therapy may prevent or delay progression of bronchiectasis and development of chronic pulmonary aspergillosis. Objective A recently commercialized lateral flow assay (Aspergillus ICT) (LDBio Diagnostics, Lyons, France) detects Aspergillus-specific antibodies in <30 minutes, requiring minimal laboratory equipment. We evaluated this assay for diagnosis of ABPA compared to diseased (asthma and/or bronchiectasis) controls. Methods ABPA and control sera collected at the National Aspergillosis Centre (Manchester, UK) and/ or from the Manchester Allergy, Respiratory and Thoracic Surgery research biobank were evaluated using the Aspergillus ICT assay. Results were read both visually and digitally (using a lateral flow reader). Serological Aspergillus-specific IgG and IgE, and total IgE titres were measured by ImmunoCAP. Results For 106 cases of ABPA versus all diseased controls, sensitivity and specificity for the Aspergillus ICT were 90.6% and 87.2%, respectively. Sensitivity for 'proven' ABPA alone (n = 96) was 89.8%, and 94.4% for 'presumed' ABPA (n = 18). 'Asthma only' controls (no bronchiectasis) and 'bronchiectasis controls' exhibited 91.4% and 81.7% specificity, respectively. Comparison of Aspergillus ICT result with Aspergillus-specific IgG and IgE titres showed no

Background Prevalence of chronic pulmonary aspergillosis (CPA) is ~3 million patients worldwide, and detection of Aspergillus -specific antibody is a critical diagnostic component. Some patients with CPA have subtle immune deficits possibly contributing to poor Aspergillus antibody production and false negative results. Materials/methods We analyzed patient data from 167 cases of clinically confirmed CPA previously evaluated by ImmunoCAP Aspergillus -specific IgG EIA, Bordier ELISA and LDBio Aspergillus IgG/IgM ICT lateral flow assay, to identify deficiencies in: mannose binding lectin (MBL), IgG, IgA, IgM, IFN gamma, IL12 or IL17 production, and/or low cell marker counts (CD4, CD19, CD56). We defined patients as ‘sero-negative’ if ImmunoCAP Aspergillus IgG was consistently and repeatedly negative (<40 mg A/L). ‘Sero-positive’ was defined as all other CPA cases. Results We found the rate of false negatives by ImmunoCAP Aspergillus IgG EIA (n = 23) to be more prevalent in patients with immunodeficiency markers, especially multiple defects. MBL deficiency combined with low CD19 cells (p < 0.001), pneumococcal antibody levels (p = 0.043), IgM (p = 0.047) or three combined (p = 0.001–0.018) or all four together (p = 0.018) were significant. The performance LDBio Aspergillus IgG/IgM ICT appears to be relatively unaffected by immunodeficiency (92.7% of ImmunoCap sero-negatives were positive). The Bordier assay performed significantly better than the ImmunoCAP assay ( P = 0.0016) for sero-negative CPA cases. Conclusions In select cases of CPA, ImmunoCAP EIA yields a false negative result, making serological diagnosis difficult. ImmunoCAP false negatives are more prevalent in patients with multiple immunological defects, who may still be positive with the LDBio Aspergillus ICT or Bordier EIA.